1. Technical Field
The present invention relates to transfer tape that has an adhesive film formed by coating a band-shaped ribbon with an adhesive film transfers the adhesive film from the band-shaped ribbon to a targeted object, thereby adhering the targeted object to another adhering object by means of the adhesive film transferred to said targeted object, and more particularly to transfer tape that maintains strong adhesive strength but can be reliably cut at a stipulated position.
2. Technical Background
A transfer tool using transfer tape that has an adhesive film formed by coating a band-shaped ribbon with an adhesive film transfers the adhesive film from the band-shaped ribbon to a targeted object, thereby adhering the targeted object to another adhering object by means of the adhesive film transferred to said targeted object. This type of transfer tool is provided with: a supply spool around which is wound the unused transfer tape; a take-up spool that takes up the band-shaped ribbon after the adhesive film is transferred; and a dispenser that is provided in an intermediate location upon the transport path between the supply spool and take-up spool and exposed to the outside.
A transfer tool of the constitution described above is used by pressing the dispenser onto the targeted object, moving the entire tool in this state, thereby transferring the adhesive film onto the targeted object and separating the transfer tool (entire tool) from the targeted object at a desired location. The adhesive film upon the band-shaped ribbon is thus cut at the dispenser onto the side on the targeted object and the side on the transfer tape.
In this operation of the transfer tool, in recent years the ease of cutting the adhesive film is considered important from the standpoint of ease of use. To wit, the adhesive film adheres the targeted object to the other adhering object so naturally it has adhesive strength. But if this adhesive strength is too high, the adhesive film cannot be easily cut when one attempts to cut it at the desired location, but rather it is stretched out in strings between the side of the targeted object and the side of the band-shaped ribbon (this phenomenon shall hereinafter be referred to as “stringiness”).
When this stringiness occurs, in the case that the terminus of the stringiness is present on the side of the targeted object, for example, dumpling-like lumps may occur when the terminuses of the stringiness are concentrated on the targeted object, or a step may occur in the state of adhesion between the targeted object and the adhering object, or gaps may occur so that good adhesion is not achieved. On the other hand, in the same manner, in the case that the terminus of the stringiness is present on the side of the band-shaped ribbon, for example, when it is used next, the dumpling-like lumps may be transferred to the targeted object or there may be occasional cases in which the transfer of the adhesive film cannot be started from the desired position. Moreover, there is a risk of the adhesive film adhering to the dispenser itself and having deleterious effects on its operation.
To solve this problem and prevent the stringiness as described above from occurring, JP-A 2000-98233 proposes providing a plurality of protrusions on the adhesive film side of the band-shaped ribbon such that they protrude in both width directions of said band-shaped ribbon, so that these protrusions make the adhesive film partially thinner. In addition, JP-A 2001-192625 proposes a pressure-sensitive transfer type adhesive tape wherein the adhesive film is disposed upon the band-shaped ribbon in a state in which it is cut to units of a stipulated size.
However, even if these proposals suppress stringiness, the adhesive film can only be cut at the positions of the predetermined protrusions or to the units of a stipulated size, so it cannot be cut at the desired positions (of size or length). In addition, there are problems in that this increases cost due to the- difficulty of manufacturing special band-shaped ribbon, and the need for facilities for coating the band-shaped ribbon with a coating cut into stipulated units.
In order to allow the adhesive film to be easily cut at the desired positions while suppressing stringiness easily and at low cost, in the past, JP-B 6-62920 proposed adhesive transfer tape wherein alginic acid is finely dispersed within an aqueous dispersal solution of the adhesive, thereby weakening the membranous character of the adhesive film and allowing it to be cut easily. In addition, JP-A 2001-240812, for example, proposes pressure-sensitive transfer adhesive tape wherein: the adhesive film contains a filler, the equation (thickness of the adhesive film)/(filler grain size)=0.6–8.0 is true, and the thickness of the adhesive film is 5–200 μm.
However, in the ones containing filler proposed in the aforementioned JP-A 2001-240812, the filler is spherical so the effect of allowing the film of the adhesive film cannot be reliably obtained, so there is a problem in that the cutting effect may not be obtained depending on the film thickness. In addition, there is also a problem in that, while the amount of filler can be easily increased or the thickness of the adhesive film can be easily made thinner, the adhesive strength conversely decreases.
In addition, with the adhesive transfer tape proposed in JP-B 6-62920, the membranous character of the adhesive film is weakened so it is easily cut, its adhesive strength may be extremely reduced due to inadequate dispersion of the alginic acid, or it may be cut at unnecessary locations, so the cutting effect cannot be reliably obtained over the entire adhesive film.
The present invention came about in order to solve the aforementioned problems and has as its object to provide transfer tape that maintains strong adhesive strength but can be reliably cut at a stipulated position.